In copending U.S. application Ser. No. 11/165,931 filed Jun. 24, 2005 entitled COILED TUBING/TOP DRIVE RIG AND METHOD ('931 application) and Ser. No. 11/294,036 filed Dec. 5, 2005 and entitled COILED TUBING/TOP DRIVE RIG AND METHOD ('036 application), both of which are incorporated herein by reference for all purposes, there is disclosed a universal rig which is capable of selectively manipulating jointed pipe as well as CT. The rig disclosed in the aforementioned '931 and '036 applications includes a mast extending upward from a rig floor or support, the mast being movable between a first position wherein a top drive carried by the mast and positioned over a wellhead can be employed, to a second position wherein a CT injector carried by the mast can be positioned over the wellhead and employed. In the rig disclosed in the '931 and '036 applications, the CT apparatus is usually mounted on the mast but in general is positioned such that the CT injector has an axis offset from the axis of the top drive which, when the mast is generally vertically aligned, is positioned over a wellhead assembly/wellbore.
As disclosed in the '931 and '036 applications, in order for the CT injector to be positioned with its axis generally coincident with the axis of the wellhead assembly/wellbore, it is necessary to pivot the mast from a substantially vertical position to a position at an angle to the vertical.
In certain cases, it may be desirable if the mast could be maintained in a substantially vertical position at all times regardless of whether earth borehole operations were being conducted using the top drive or the CT injector which, as noted above, has an axis which is not coincident with the axis of the top drive. Thus, with the mast in the vertical position, both top drive and CT operations could be conducted.